Battery charger



FIG. 1 is a perspective view of a battery charger:

FIG. 2 is a front view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a right-side view thereof;

FIG. 5 is a left-side view thereof;

FIG. 6 is a rear view thereof; and,

FIG. 7 is a bottom view thereof.

The broken lines depict environmental subject matter only and form no part of the claimed design. 

The ornamental design for a battery charger, as shown and described. 